1. Field of the Invention
The present invention relates to a method of reusing a coated substrate having an easily removable coating which is fixed to the surface of material from which the deposit is easily removed with water, such that the coated material can be repeatedly cleaned easily.
2. Description of Related Art
Hitherto it was difficult to remove a water-insoluble deposit from a material surface. For example, liquid oil should be cleaned by water containing a surfactant with considerable labor, or by an organic solvent which is harmful to both the human body and the environment.
Since a waxy or solid deposit is difficult to remove using the surfactant, it should be removed by the organic solvent or mechanically scraped off, which requires heavy work. But such deposit may not be completely removed, or the material to which the deposit is adhered may be damaged. In many cases, the waxy or solid deposit may not be removed.
It is possible to remove the deposit by forming a releasable or soluble coating on the material and removing the deposit together with the coating. However, whenever the coating is removed, a fresh coating must be reformed, or the removed coating generates an additional waste. Therefore, this technique does not provide a viable solution.
As a coating from which the deposit can be repeatedly removed, a coating of polyterafluoroethylene (hereinafter referred to as "PTFE", (for example, TEFLON.TM. of DuPont) is known. However, it is not widely used since it is expensive, and the kind of surface on which the PTFE coating can be formed is limited, or it has poor transparency.
It is highly desired to develop a coating such that a deposit can be repeatedly removed from the material surface and which solves the above problems.
As explained above, to remove the deposit from the material is surface, a large amount of work is required, or some other methods applied which use an organic solvent which is harmful to the human body and the environment. In the case of overhead projector (OHP) films or office automation papers such as copying papers, they are used and wasted on a large scale to cause an environmental problem, since ink cannot be removed from their surfaces. This is because there is no coating from which the deposit, such as the ink, is repeatedly removed with ease and which is cheap and has good flexibility in use.